We're talking about nations, not people, so I don't think "GDP per capita" is relevant. USA has by far the highest total GDP. http://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nomin...
Foreign policy, which is decided by governments that tax the aggregate population (and thus draw from the GDP)? Not in the slightest.
Foreign policy, affected by GDP, certainly plays a role in this.